HUNTERSVILLE, N.C. -- J.D. Gibbs, son of Pro Football Hall of Fame coach Joe Gibbs and a co-founder of Joe Gibbs Racing with his father, died Friday after a four-year battle with a degenerative neurological disease. He was 49.

"Joe Gibbs Racing appreciates everyone's respect for the privacy of the Gibbs family during this difficult time," the team said in a statement.

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Denny Hamlin admitted that J.D. Gibbs "took a chance" by signing him to a deal years ago. On Sunday, Hamlin returned the favor by putting his ailing boss in Victory Lane at the Daytona 500.

J.D. Gibbs was president of JGR from 1997 to 2015. JGR won four NASCAR Cup titles under his leadership with Bobby Labonte in 2000, Tony Stewart in 2002 and 2005 and Kyle Busch in 2015.

"I want to make sure that everybody here [knows] J.D.'s input with our race team, and everything when Tony [Stewart] was there, was so critical," Joe Gibbs told reporters during the championship-contending owners news conference in November.

"Lots of times I get put in a position where I get up here and get to represent our company, but I just want to reflect on everything that J.D. has done, and the fact that he's not with us [at the track]."

Joe Gibbs runs his NASCAR race team. His other son, Coy, has helped run the race team the past three years.

J.D. Gibbs is credited with giving Denny Hamlin his first opportunity to compete in NASCAR at a national level. Hamlin posted a tribute to Gibbs late Friday night on Twitter.

His car. His number. His signature above my door. I will always be grateful for what His family did for mine and the opportunity he gave me 14 years ago. Now more than ever #doitforJD

In May 2015, the team announced J.D. Gibbs had begun treatment for symptoms impacting areas of brain function, including speech and processing issues.

The team said doctors determined that the cause was "head injuries likely suffered earlier in life," but they did not determine one specific injury. A former defensive back and quarterback at the College of William & Mary from 1987 to 1990, Gibbs also had a short career as a race car driver and enjoyed other extreme activities.

"We were privileged to watch J.D. Gibbs grow within the sport, displaying an endearing personality, a keen eye for talent and the strong business acumen that helped grow Joe Gibbs Racing into a preeminent NASCAR team," NASCAR Chairman Jim France said in a statement.